7xx aluminum casting alloys, and methods for making the same

Abstract

New shape-cast 7xx aluminum alloys products are disclosed. The new shape-cast products may include from 3.0 to 8.0 wt. % Zn, from 1.0 to 3.0 wt. % Mg, where the wt. % Zn exceeds the wt. % Mg, from 0.35 to 1.0 wt. % Cu, where the wt. % Mg exceeds the wt. % Cu, from 0.05 to 0.30 wt. % V, from 0.01 to 1.0 wt. % of at least one secondary element (Mn, Cr, Zr, Ti, B, and combinations thereof), up to 0.50 wt. % Fe, and up to 0.25 wt. % Si, the balance being aluminum and other elements, wherein the aluminum casting alloy include not greater than 0.05 wt. % each of the other elements, and wherein the aluminum casting alloy includes not greater than 0.15 wt. % in total of the other elements.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This patent application is a continuation of U.S. patent application Ser. No. 14 / 694,109, filed Apr. 23, 2015, which claims benefit of priority of U.S. Provisional Patent Application No. 61 / 986,249, filed Apr. 30, 2014, both entitled “IMPROVED 7XX ALUMINUM CASTING ALLOYS, AND METHODS FOR MAKING THE SAME”, each of which is incorporated herein by reference in its entirety.BACKGROUND[0002]Aluminum alloys are useful in a variety of applications. However, improving one property of an aluminum alloy without degrading another property is elusive. For example, it is difficult to increase the strength of an aluminum casting alloy without affecting other properties such as castability, elongation or stress corrosion cracking. See, for example, U. S. Patent Application Publication No. 2008 / 0066833.SUMMARY OF THE DISCLOSURE[0003]Broadly, the present patent application relates to improved 7xx aluminum casting alloys, and methods for producing the same...

AI Technical Summary

Benefits of technology

[0003]Broadly, the present patent application relates to improved 7xx aluminum casting alloys, and methods for producing the same. The new 7xx aluminum casting alloys may realize, for instance, an improved combination of at least two of strength, corrosion resistance, castability, and fatigue failure resistance, among other properties.

[0007]The new 7xx aluminum casting alloys generally include copper and in the range of from 0.35 to 1.0 wt. % Cu. The amount of magnesium exceeds the amount of copper. As shown below, copper may facilitate, for example, improved corrosion resistance and / or strength. In one embodiment, a new 7xx aluminum casting alloy includes not greater than 0.95 wt. % Cu. In another embodiment, a new 7xx aluminum casting alloy includes not greater than 0.90 wt. % Cu. In yet another embodiment, a new 7xx aluminum casting alloy includes not greater than 0.85 wt. % Cu. In another embodiment, a new 7xx aluminum casting alloy includes not greater than 0.80 wt. % Cu. In one embodiment, a new 7xx aluminum casting alloy includes at least 0.40 wt. % Cu. In another embodiment, a new 7xx aluminum casting alloy includes at least 0.45 wt. % Cu. In yet another embodiment, a new 7xx aluminum casting alloy includes at least 0.50 wt. % Cu. In another embodiment, a new 7xx aluminum casting alloy includes at least 0.55 wt. % Cu. In yet another embodiment, a new 7xx aluminum casting alloy includes at least 0.60 wt. % Cu.

[0008]The new 7xx aluminum casting alloys generally include from 0.05 to 0.30 wt. % V. As shown below, vanadium may facilitate, for example, improved corrosion resistance. In one embodiment, a new 7xx aluminum casting alloy includes not greater than 0.25 wt. % V. In another embodiment, a new 7xx aluminum casting alloy includes not greater than 0.20 wt. % V. In yet another embodiment, a new 7xx aluminum casting alloy includes not greater than 0.18 wt. % V. In another embodiment, a new 7xx aluminum casting alloy includes not greater than 0.16 wt. % V. In yet another embodiment, a new 7xx aluminum casting alloy includes not greater than 0.15 wt. % V. In another embodiment, a new 7xx aluminum casting alloy includes not greater than 0.14 wt. % V. In yet another embodiment, a new 7xx aluminum casting alloy includes not greater than 0.13 wt. % V. In another embodiment, a new 7xx aluminum casting alloy includes not greater than 0.12 wt. % V. In yet another embodiment, a new 7xx aluminum casting alloy includes not greater than 0.11 wt. % V. In one embodiment, a new 7xx aluminum casting alloy includes at least 0.06 wt. % V. In another embodiment, a new 7xx aluminum casting alloy includes at least 0.07 wt. % V. In yet another embodiment, a new 7xx aluminum casting alloy includes at least 0.08 wt. % V. In another embodiment, a new 7xx aluminum casting alloy includes at least 0.09 wt. % V. Not greater than 0.15 wt. % V should be used when fatigue properties are important.

Problems solved by technology

However, improving one property of an aluminum alloy without degrading another property is elusive.

For example, it is difficult to increase the strength of an aluminum casting alloy without affecting other properties such as castability, elongation or stress corrosion cracking.